Is the Schwarzchild Metric Accurate in Predicting Black Holes?

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Discussion Overview

The discussion revolves around the accuracy of the Schwarzschild metric in predicting black holes, with a focus on a proposed modification to the metric. Participants explore theoretical implications, mathematical formulations, and the validity of the original and modified solutions.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant recounts a lecture where a researcher claimed that the Schwarzschild solution is incorrect and proposed a modification involving a new term, suggesting that the term should be r->(r^3+a^3)^(1/3) where a = 2GM/c^2.
  • Another participant questions the validity of the proposed modification, arguing that it does not reduce to the Minkowski metric in flat spacetime, which they assert is a requirement for any valid metric.
  • A different participant suggests an alternative interpretation of the proposed modification, indicating that it could yield a correction to Newton's law and maintain spherical symmetry, but expresses uncertainty about its compliance with Einstein's field equations.
  • One participant confirms that the proposed modification does not satisfy Einstein's field equations, specifically R_{\mu\nu}=0.

Areas of Agreement / Disagreement

Participants express disagreement regarding the validity of the proposed modification to the Schwarzschild metric. While some find merit in the new formulation, others assert it fails to meet established criteria and does not satisfy Einstein's field equations. The discussion remains unresolved with competing views on the accuracy of the Schwarzschild metric and the proposed changes.

Contextual Notes

There are limitations in the discussion regarding the assumptions underlying the proposed modifications and their implications for black hole predictions. The mathematical steps involved in verifying compliance with Einstein's field equations are not fully resolved.

jimbo007
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hi
recently i attended a lecture where a current researcher from my university was talking about black holes and the schwarzchild metric. basically he was saying no current theory predicts black holes and the schwarzchild solution is not actually correct, his solution was accepted because apparently he was a highly influential mathematician.
he said that the r term in the schwarzchild metric should actually be
r->(r^3+a^3)^(1/3) where a = 2GM/c^2
as you see the a term is quite small (G=gravitation constant and c is the speed of light).
my understanding of the majority of his talk was a bit shakey but he didnt seem like a nut as there were a few other professors attending the lecture also and they couldn't point out any flaws in his argument.
he reckons that no one else has pointed this mistake out yet and has submitted his report to be published in a journal.
 
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jimbo007 said:
hi
recently i attended a lecture where a current researcher from my university was talking about black holes and the schwarzchild metric. basically he was saying no current theory predicts black holes and the schwarzchild solution is not actually correct, his solution was accepted because apparently he was a highly influential mathematician.
he said that the r term in the schwarzchild metric should actually be
r->(r^3+a^3)^(1/3) where a = 2GM/c^2
as you see the a term is quite small (G=gravitation constant and c is the speed of light).
my understanding of the majority of his talk was a bit shakey but he didnt seem like a nut as there were a few other professors attending the lecture also and they couldn't point out any flaws in his argument.
he reckons that no one else has pointed this mistake out yet and has submitted his report to be published in a journal.


1) Which journal?

2) Assuming you're presenting that correctly then the r term reduces to r for flat space time, which is wrong. It should reduce to 1, the value for the minkowski metric. Just to check you're saying that according to him it should be:
[tex] \left( \begin{array}{cccc}-(1-\frac{2M}{r}) & 0 & 0 & 0 \\ 0 & r^2 & 0 & 0 \\ 0 & 0 & r^2sin^2(\theta) & 0 \\ 0 & 0 & 0 & (r^3 + (\frac{2GM}{c^2})^3)^(1/3) \end{array} \right)[/tex]

Which means that for space far removed from any source of mass, i.e., falt space time we get:
[tex] \left( \begin{array}{cccc} -1 & 0 & 0 & 0 \\ 0 & r^2 & 0 & 0 \\ 0 & 0 & r^2sin^2(\theta) & 0 \\ 0 & 0 & 0 & r \end{array}\right)[/tex]

Which is not the Minkowski metric, however we know, from all the experimental verification of SR that the minkowksi metric is valid, so he cannot be right. There are problems with relativity, but not those kinds. The very fact that this guy claimed the Scwarzschild's solution was only accepted because of his personal influence is very big crackpot give away.
 
Last edited:
I think he meant:

[tex] \left( \begin{array}{cccc}1-( \frac{2MG}{c^2 (r^3 + (\frac{2GM}{c^2})^3)^{1/3}}) & 0 & 0 & 0 \\ 0 & -(1-\frac{2MG}{c^2 (r^3 + (\frac{2GM}{c^2})^3)^{1/3}})^{-1} & 0 & 0 \\ 0 & 0 & -(r^3 + (\frac{2GM}{c^2})^3)^{2/3} & 0 \\ 0 & 0 & 0 & -(r^3 + (\frac{2GM}{c^2})^3)^{2/3} sin( \theta )^2 \end{array} \right)[/tex]

So everywhere in the Schwarzschild metric replace r with the new r.

This does yield the flat metric for large r. It also means a correction to Newtons law yielding a potential V=MG/(r^3+2GM/c^2)^(1/3). The metric is still spherically symmetric. I can't find any reason why this cannot be correct.

It is correct that this solution has no r for which a term diverges (only r=0) so it would does not automatically imples a black hole.

I would like to see why the original solution cannot be correct, or why this one is better, so I'm also interested in the article...But I'm not sure this resultobey's Einsteins field equations. Anybody an idea?
 
Last edited:
I have just checked it, it does not satisfy the Einstein's field equations: [tex]R_{\mu\nu}=0[/tex].


Kenneth
 
I guess the problem is solved then...
 

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